The invention relates in general to cameras that generate digital images for storage on a removable storage medium. More specifically, the invention relates to a camera that includes a working memory that stores a working image which is updated for each subsequent exposure operation, wherein the working image can be displayed in a quick review mode on a display screen regardless of whether the removable storage medium is attached to the camera. The invention is particularly directed to a hybrid camera that includes both a digital imaging system and a silver-halide imaging system, wherein a working image can be displayed in the quick review mode regardless of whether the removable storage medium is attached to the camera or a film cartridge is loaded in the camera.
There have been a number of conventional electronic still cameras and hybrid cameras either proposed and/or commercially developed. In each of the conventional cameras, electronic images are generally captured and stored on a recording medium that can be removed from the camera or transmitted by a data link to a remote location. Early electronic and hybrid cameras, for example, utilized magnetic recording disks as an image storage medium, while more recent developments in electronics have led to the use of semiconductor device memory cards. It is desirable to include a display screen on the camera to permit images captured and stored on the memory cards to be reviewed. U.S. Pat. No. 4,742,369 issued to Ishii et al., for example, describes a camera that includes a display device so that an operator can confirm whether the captured image is acceptable. Image display devices large enough to display a digital image of acceptable size, such as a large array liquid crystal device, still consume a relatively large amount of power when active. Accordingly, the batteries of the camera can be quickly drained if the display device is utilized during imaging operations. Further, it would be desirable to be able to review the last captured image regardless of whether the removable memory medium was attached to the camera.
In view of the above, it is an object of the invention to provide a camera that incorporates an apparatus for allowing the camera operator to review a last captured image without causing a large energy drain. It is a further object to provide a camera in which the last captured image can be reviewed regardless of whether a removable memory medium is attached to the camera.
The invention provides a camera that incorporates a working memory for storing a working image corresponding to the last captured image. The working image is displayed on a display screen in a quick review mode of operation in response to a quick review signal entered by the camera operator. The display screen is kept in an inactive state until the quick review signal is entered, and returns to an inactive state after a predetermined time period or when the quick review signal is discontinued thereby conserving energy. In addition, the working image is displayed in the quick review mode regardless of whether a removable memory medium is attached to the camera or, in the case of a hybrid camera, whether a film cartridge is contained in the camera.
Specifically, a camera in accordance with the invention may include digital imaging means for generating a digital image representative of a subject scene; fixed working memory means for receiving and storing the digital image generated by the digital imaging means as a working image; a non-volatile memory for storing digital images; a display screen; and control processing means for controlling the operation of the digital imaging means, the fixed working memory means and the display screen. In accordance with the invention, the control processing means generates a digital mode image from the working image stored in the working memory and transfers the digital mode image to the non-volatile memory while retaining the working image in the working memory. The control processing means also selectively generates a display image from a digital mode image stored in the non-volatile memory and transfers the display image to the display screen for display. Finally, the control processing means selectively generates a quick review image from the working image stored in the working memory and supplies the quick review image to the display screen for display without requiring availability of the non-volatile memory.
The-digital imaging means may generate a plurality of digital images under control of the control processing means; so that, each subsequent one of the plurality of digital images replaces a preceding one of the plurality of digital images as the working image stored in the working memory, whereby the working image is representative of the last subject scene imaged by the camera. A hybrid version of the camera may include a photographic imaging means for imaging the subject scene onto a photographic film plane of the camera under control of the control processing means. The control processing means may include a camera operator interface that includes an image mode selector for selecting one of a film imaging mode, a hybrid imaging mode and the digital imaging mode of operation. The photographic imaging means may image the subject scene onto the photographic image plane in the film imaging mode and the hybrid imaging mode to generate a corresponding photographic film image on a photographic film located at the photographic imaging plane that corresponds with the digital image generated by the digital imaging means. The control processing means may generate a film mode digital image from the working image in the film imaging mode of operation and stores the film mode digital image in an internal fixed base camera memory of the camera, and wherein the control processing means selectively generates a display image from the film mode digital image and transfers the display image to the display screen for display.
The camera may include a removable interface connection means for receiving a removable memory device; wherein the non-volatile memory is comprised in a removable memory, such as a card coupled to the interface connection means. The control processing means may generate a hybrid mode digital image from the working image in the hybrid mode of operation and transfer the hybrid mode digital image to the removable memory interface connection means for storage on the memory card. The control processing means may selectively generate a display image from a hybrid mode digital image stored on the memory card coupled to the memory interface connection means and transfers the display image to the display screen for display.
The control processing means may activate the display screen for a predetermined time period to display the quick review image. The camera operator interface may include a quick review switch; so that, the control processing means activates the display screen to display the quick review image as long as the quick review switch is activated. Means may be included for storing the quick review image in the non-volatile memory or in removable memory.
Other features and advantages of the invention will become apparent and appreciated after review of the following detailed description of the invention, the appended claims and the drawings.